During 1979-1980, we plan to continue studies on antihemophilic factor (AHF), von Willebrand factor (vWF) platelet aggregating factor (PAF); (2) Defibrination; (3) Affinity chromatography; (4) Polyelectrolytes; (5) Platelets; 1. AHF/vWF - we plan to purify vWF free of AHF (about 12,000 X purified); AHF free of vWF (about 500,000 X purified); continue the characterization of vWF; initiate the characterization of AHF; purify low M AHF; and investigate the activation of factor X by the interaction of highly purified AHF, factor 1Xa, Ca ions and phospholipid, using the factor X glycopeptide assay. 2. Defibrination - improve our method for isolating pure FR-antigen from plasma; study the structure of the antigen from patients with defibrination and thrombotic states; characterize the pathogenic enzymes responsible for serum FR-antigen in these patients; correlate these results with the clinical findings to optimize diagnosis and treatment. 3. Affinity chromatography - develop new affinity absorbents for the isolation and purification of various proteins; develop the triazine-based methodology to assure bonding of the ligands without steric hindrance of the protein-ligand complex; isolate and purify coagulation factors II, VII, IX and X, alpha-l-antiprotease, and inter-alpha-trypsin inhibitor. 4. Polyelectrolyte fractionation - explore the mode of action of polyelectrolytes in the fractionation procedures we have developed for isolation of the clinically useful plasma proteins. 5. Platelets -identify the fibrinogen receptor by photo-affinity methods; determine chemical groups affecting micro-electrophoresis; ascertain relationship of platelet alpha-actinin to glycoprotein IIIa; determine the role of platelets in clotting with special reference to vWF and AHF.